Access-category-based multi-user trigger frames

ABSTRACT

During operation, an interface circuit in an electronic device may receive, from a second electronic device (such as an access point in a WLAN), an uplink trigger frame that may specify an access category. In response to the uplink trigger frame, the electronic device may first include data associated with the specified access category in one or more frames, and then may transmit the one or more frames to the second electronic device. Moreover, when all the data associated with the specified access category has been transmitted or when there is no data associated with the specified access category, and when there is leftover time in an allocation associated with the uplink trigger frame, the interface circuit may transmit the one or more frames to the second electronic device with additional data associated with another access category that is different from the specified access category.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/327,865, entitled “ACCESS-CATEGORY-BASED MULTI-USERTRIGGER FRAMES” filed Apr. 26, 2016, the content of which isincorporated herein by reference in its entirety for all purposes.

FIELD

The described embodiments relate, generally, to wireless communicationsamong electronic devices in a wireless local area network (WLAN),including electronic devices and techniques for providing trigger framesthat specify an access category.

BACKGROUND

Many electronic devices communicate with each other using wireless localarea networks (WLANs), such as those based on a communication protocolthat is compatible with an Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 standard (which is sometimes referred to as‘Wi-Fi’). In media access control (MAC) layers in IEEE 802.11-compatibleinterface circuits, traffic from an upper layer typically includespriority tags. These tags are usually considered quality-of-service(QoS) requirements of the current traffic. In response, the MAC layersin the IEEE 802.11-compatible interface circuits may map the prioritytags to corresponding access categories (ACs) in order to meet the QoSrequirements.

Moreover, traffic in different access categories usually uses or hasdifferent content-window sizes and inter-frame spacings (IFSs) toprovide QoS differentiation. For example, traffic with a lower-priorityaccess category may have a larger contention-window size, which resultsin longer backoff time and, thus, this lower-priority access categorymay have a lower QoS in access to the shared medium or channel. Notethat existing IEEE 802.11 standards recognize four hierarchical accesscategories (ACs), including: AC_VO (voice), AC_VI (video), AC_BE (besteffort) and AC_BK (background), which provide the foundation for QoS inWi-Fi networks.

Recently, in IEEE 802.11 ax standard, it has been proposed thattransmissions from different electronic devices or stations, such asstation A and station B, may be treated equally regardless of the accesscategories associated with their transmissions (and, thus, regardless oftheir QoS requirements). In particular, in the proposed IEEE 802.11axstandard, the backoff time for transmissions from stations A and B maybe the same, even though they may have different access categories.

Consequently, this proposal may eliminate the ability to provide accesscategory-based QoS differentiation in IEEE 802.11ax. This loss of QoSdifferentiation may degrade the communication performance for thehigher-priority access-category traffic, and, thus, may frustrate usersof the electronic devices and degrade the user experience.

SUMMARY

Some embodiments that relate to an electronic device that receives anuplink trigger frame from a second electronic device are described. Inparticular, during operation, an interface circuit in the electronicdevice may receive the uplink trigger frame from a second electronicdevice, such as an access point in a WLAN. The uplink trigger frame mayspecify an access category. In response to the uplink trigger frame, theelectronic device may transmit one or more frames to the secondelectronic device with data associated with the specified accesscategory.

Note that the uplink trigger frame may include a multi-user triggerframe.

Moreover, when all the data associated with the specified accesscategory has been transmitted or when there is no data associated withthe specified access category, and when there is leftover time in anallocation associated with the uplink trigger frame, the interfacecircuit may transmit the one or more frames to the second electronicdevice with additional data associated with another access category thatis different from the specified access category.

Furthermore, the trigger frame may be preceded by a contention-windowsize and may be followed by an inter-frame spacing associated with thespecified access category.

Other embodiments include operation with and/or by the second electronicdevice.

For example, the interface circuit in the second electronic device may:assemble a downlink orthogonal frequency-division multiple access(OFDMA) frame having a primary access category, where the secondelectronic device first includes data associated with the primary accesscategory in the downlink OFDMA frame; and transmits the downlink OFDMAframe to the second electronic device. Moreover, when all the dataassociated with the primary access category has been included (ortransmitted) or when there is no data associated with the primary accesscategory, the interface circuit in the second electronic device mayinclude additional data in the downlink OFDMA frame associated withanother access category that is different from the primary accesscategory.

In some embodiments, the interface circuit in the second electronicdevice assembles a downlink multi-traffic-identifier (TID) aggregatemedia access control protocol data unit (AMPDU) having the primaryaccess category, and then transmits the downlink multi-TID AMPDU to thesecond electronic device. The downlink multi-TID AMPDU may includeadditional data associated with a different access category when abackoff counter associated with the different access category has apredefined value (such as zero) and/or when all the data associated withthe primary access category has been included (or transmitted) and thereis leftover duration in the downlink multi-TID AMPDU.

Other embodiments describe an interface circuit in the electronic deviceor the second electronic device.

Other embodiments describe a computer-program product for use with theinterface circuit in the electronic device or the second electronicdevice. This computer-program product includes instructions for at leastsome of the aforementioned operations performed by the interface circuitin the electronic device or the second electronic device.

Other embodiments describe a method for communicating one or moreframes. The method includes at least some of the aforementionedoperations performed by the interface circuit in the electronic deviceor the second electronic device.

This Summary is provided for purposes of illustrating some exemplaryembodiments, so as to provide a basic understanding of some aspects ofthe subject matter described herein. Accordingly, it will be appreciatedthat the above-described features are only examples and should not beconstrued to narrow the scope or spirit of the subject matter describedherein in any way. Other features, aspects, and advantages of thesubject matter described herein will become apparent from the followingDetailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and serve only toprovide examples of possible structures and arrangements for thedisclosed systems and techniques for intelligently and efficientlymanaging communication between multiple associated user devices. Thesedrawings in no way limit any changes in form and detail that may be madeto the embodiments by one skilled in the art without departing from thespirit and scope of the embodiments. The embodiments will be readilyunderstood by the following detailed description in conjunction with theaccompanying drawings, wherein like reference numerals designate likestructural elements.

FIG. 1 is a block diagram illustrating an example of electronic devicescommunicating wirelessly.

FIG. 2 is a flow diagram illustrating an example of a method forcommunicating one or more frames using one of the electronic devices inFIG. 1.

FIG. 3 is a flow diagram illustrating an example of a method forproviding an uplink trigger frame using one of the electronic devices inFIG. 1.

FIG. 4 is a flow diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 5 is a timing diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 6 is a block diagram illustrating an example of a trigger framethat includes information specifying an access category.

FIG. 7 is a timing diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 8 is a drawing illustrating an example of communication using amulti-traffic-identifier (TID) aggregate media access control protocoldata unit (AMPDU).

FIG. 9 is a block diagram illustrating an example of one of theelectronic devices of FIG. 1.

Note that like reference numerals refer to corresponding partsthroughout the drawings. Moreover, multiple instances of the same partare designated by a common prefix separated from an instance number by adash.

DETAILED DESCRIPTION

An electronic device that receives an uplink trigger frame from a secondelectronic device (such as an access point in a wireless local areanetwork (WLAN)) is described. During operation, an interface circuit inthe electronic device may receive, from the second electronic device, anuplink trigger frame that may specify an access category. In response tothe uplink trigger frame, the electronic device may first include dataassociated with the specified access category in one or more frames, andthen may transmit the one or more frames to the second electronicdevice. Moreover, when all the data associated with the specified accesscategory has been transmitted or when there is no data associated withthe specified access category, and when there is leftover time in anallocation associated with the uplink trigger frame, the interfacecircuit may transmit one or more frames (which may be the same frames ordifferent frames) to the second electronic device with additional dataassociated with another access category that is different from thespecified access category. Furthermore, the trigger frame may betransmitted using or in conjunction with a contention-window size and aninter-frame spacing associated with the specified access category, sothat there is a difference in how fast different access categoriesaccess a shared medium.

By allowing the second electronic device to specify the access categoryin the trigger frame, this communication technique may allow theelectronic device and the second electronic device to differentiatetraffic according to associated quality of service (QoS) requirements.In particular, the communication technique may facilitate different QoSbased on access categories associated with different types of data.Consequently, the communication technique may improve the communicationperformance, e.g., by reducing the access time or latency for accesscategories that have higher QoS. Moreover, by improving thecommunication performance, the communication technique may improve theuser experience when using the electronic device or the secondelectronic device, and thus may increase customer satisfaction andretention.

Note that the communication technique may be used during wirelesscommunication between electronic devices in accordance with acommunication protocol, such as: an IEEE 802.11 standard (which issometimes referred to as Wi-Fi). For example, the communicationtechnique may be used with IEEE 802.11ax, which is used as anillustrative example in the discussion that follows. However, thiscommunication technique may also be used with a wide variety of othercommunication protocols, and in electronic devices (such as electronicdevices and, in particular, mobile devices) that can incorporatemultiple different radio access technologies (RATs) to provideconnections through different wireless networks that offer differentservices and/or capabilities.

In particular, an electronic device can include hardware and software tosupport a wireless personal area network (WPAN) according to a WPANcommunication protocol, such as those standardized by the Bluetooth®Special Interest Group (in Kirkland, Wash.) and/or those developed byApple (in Cupertino, Calif.) that are referred to as an Apple WirelessDirect Link (AWDL). Moreover, the electronic device can communicate via:a wireless wide area network (WWAN), a wireless metro area network(WMAN) a WLAN, near-field communication (NFC), a cellular-telephone ordata network (such as using a third generation (3G) communicationprotocol, a fourth generation (4G) communication protocol, e.g., LongTerm Evolution or LTE, LTE Advanced (LTE-A), a fifth generation (5G)communication protocol, or other present or future developed advancedcellular communication protocol) and/or another communication protocol.

The electronic device, in some embodiments, can also operate as part ofa wireless communication system, which can include a set of clientdevices, which can also be referred to as stations or client electronicdevices, interconnected to an access point, e.g., as part of a WLAN,and/or to each other, e.g., as part of a WPAN and/or an ‘ad hoc’wireless network, such as a Wi-Fi direct connection. In someembodiments, the client device can be any electronic device that iscapable of communicating via a WLAN technology, e.g., in accordance witha WLAN communication protocol. Furthermore, in some embodiments, theWLAN technology can include a Wi-Fi (or more generically a WLAN)wireless communication subsystem or radio, and the Wi-Fi radio canimplement an IEEE 802.11 technology, such as one or more of: IEEE802.11a; IEEE 802.11b; IEEE 802.11g; IEEE 802.11-2007; IEEE 802.11n;IEEE 802.11-2012; IEEE 802.11ac; IEEE 802.11ax, or other present orfuture developed IEEE 802.11 technologies.

In some embodiments, the second electronic device can act as acommunications hub that provides access to a WLAN and/or to a WWAN and,thus, to a wide variety of services that can be supported by variousapplications executing on the second electronic device. Thus, the secondelectronic device may include an ‘access point’ that communicateswirelessly with other electronic devices (such as using Wi-Fi), and thatprovides access to another network (such as the Internet) via IEEE 802.3(which is sometimes referred to as ‘Ethernet’).

Additionally, it should be understood that the electronic devicesdescribed herein may be configured as multi-mode wireless communicationdevices that are also capable of communicating via different 3G and/orsecond generation (2G) RATs. In these scenarios, a multi-mode electronicdevice or UE can be configured to prefer attachment to LTE networksoffering faster data rate throughput, as compared to other 3G legacynetworks offering lower data rate throughputs. For example, in someimplementations, a multi-mode electronic device is configured to fallback to a 3G legacy network, e.g., an Evolved High Speed Packet Access(HSPA+) network or a Code Division Multiple Access (CDMA) 2000Evolution-Data Only (EV-DO) network, when LTE and LTE-A networks areotherwise unavailable.

In accordance with various embodiments described herein, the terms‘wireless communication device,’ ‘wireless device,’ ‘electronic device,’‘mobile device,’ ‘mobile station,’ ‘wireless station,’ ‘wireless accesspoint,’ ‘station,’ ‘access point’ and ‘user equipment’ (UE) may be usedherein to describe one or more consumer electronic devices that may becapable of performing procedures associated with various embodiments ofthe disclosure.

FIG. 1 presents a block diagram illustrating an example of electronicdevices communicating wirelessly. In particular, electronic devices 110(such as a smartphone, a laptop computer, a notebook computer, a tablet,a wearable computing device, or another such electronic device) andaccess point 112 may communicate wirelessly in a wireless local areanetwork (WLAN) using an IEEE 802.11 communication protocol. Thus,electronic devices 110 may be associated with access point 112. Forexample, electronic devices 110 and access point 112 may wirelesslycommunicate while: detecting one another by scanning wireless channels,transmitting and receiving beacons or beacon frames on wirelesschannels, establishing connections (for example, by transmitting connectrequests), and/or transmitting and receiving packets or frames (whichmay include the request and/or additional information, such as data, aspayloads). Access point 112 may provide access to a network, such as theInternet, via an Ethernet protocol, and may be a physical access pointor a virtual access point that is implemented on a computer.

As described further below with reference to FIG. 9, electronic devices110 and access point 112 may include subsystems, such as a networkingsubsystem, a memory subsystem, and a processor subsystem. In addition,electronic devices 110 and access point 112 may include radios 114 inthe networking subsystems. More generally, electronic devices 110 andaccess point 112 can include (or can be included within) any electronicdevices with networking subsystems that enable electronic devices 110and access point 112 to wirelessly communicate with one or more otherelectronic devices. This can include transmitting beacons on wirelesschannels to enable electronic devices to make initial contact with or todetect each other, followed by exchanging subsequent data/managementframes (such as connect requests) to establish a connection, configuringsecurity options (e.g., IPSec), transmitting and receiving packets orframes via the connection, etc.

As can be seen in FIG. 1, wireless signals 116 (represented by a jaggedline) are communicated by radios 114 in electronic devices 110 andaccess point 112, respectively. For example, as noted previously,electronic device 110-1 and access point 112 may exchange packets usinga Wi-Fi protocol in a WLAN. As noted previously, different types of datain this communication may have different QoS requirements, such asdifferent access categories. However, in existing proposals for the IEEE802.11ax standard the different types of data may be treated equally,such that the associated transmissions are not differentiated based onthe access categories. Consequently, in these proposals, there would notbe a difference in the time needed to access the shared medium orcommunication channel for the different access categories. Inparticular, frames that include different types of data having differentaccess categories, which are transmitted by electronic devices 110 inresponse to a trigger frame from access point 112, may have the samebackoff time. This represents a departure from the approach used inprevious IEEE 802.11 standards.

In order to treat data traffic according to their QoS requirements and,thus, in order to differentiate the associated transmissions (e.g., byusing a different backoff time for data transmissions that have a lowerQoS requirement or a lower-priority access category in a hierarchy),access point 112 may provide an uplink trigger frame to electronicdevice 110-1 that includes information or an indication that specifiesan access category. For example, the uplink trigger frame may be anuplink multi-user trigger frame that is provided to electronic devices110.

In response, electronic device 110-1 may transmit one or more framesthat include data associated with the access category to access point112. In particular, electronic device 110-1 may assembly the one or moreframes with any pending data associated with the access category. Forexample, the trigger frame may specify AC_VO, and, in response, the oneor more frames may preferentially include any voice data that is pendingin a queue. Then, electronic device 110-1 may transmit the one or moreframes to access point 112.

Moreover, when all the data associated with the specified accesscategory has been transmitted or when there is no data associated withthe specified access category (which may include embodiments where therenever was any data associated with the specified access category whenthe uplink trigger frame was received), and when there is leftover timein an allocation (such as a resource allocation) associated with theuplink trigger frame, electronic device 110-1 may assemble and then maytransmit the one or more frames to access point 112 with additional dataassociated with at least another access category that is different fromthe specified access category. For example, the additional data may beselected according to an access-category hierarchy (such as AC_VO,AC_VI, AC_BE and AC_BK) or based on demand (such as when there is a lotof data from another access category in a queue, e.g., AC_BE). Note thatinclusion of the additional data in the one or more frames is sometimesreferred to as ‘non-triggered access category.’

While remaining time in an allocation may be filled using the additionaldata associated with at least the other access category, in someembodiments the remaining space in the one or more frames may be padded.

Furthermore, as described further below with reference to FIG. 5, thetrigger frame may be transmitted by access point 112 using or inconjunction with a contention-window size and an inter-frame spacingassociated with the specified access category, so that there is adifference in how fast different access categories access a sharedmedium in the WLAN. Stated differently, the trigger frame may betransmitted by access point 112 with a backoff time that corresponds tothe contention-window size associated with the specified accesscategory.

While the preceding discussion illustrated QoS provisioning duringuplink communication, a similar approach may be used during downlinkcommunication, in particular during a downlink multi-user transmission.For example, as described further below with reference to FIG. 7, accesspoint 112 may assemble a downlink orthogonal frequency-division multipleaccess (OFDMA) frame having a primary access category. Then, accesspoint 112 may transmit the downlink OFDMA frame to one or moreelectronic devices 110, such as electronic device 110-1. Note thataccess point 112 may first include data associated with the primaryaccess category, such as any pending data associated with the primaryaccess category, in the downlink OFDMA frame. When all the dataassociated with the primary access category has been included in thedownlink OFDMA (or has been transmitted) or when there is no dataassociated with the primary access category (which may includeembodiments where no data existed), access point 112 may includeadditional data in the downlink OFDMA frame associated with at leastanother access category that is different from the primary accesscategory. (Alternatively, access point 112 may pad the downlink OFDMAframe.)

As described further below with reference to FIG. 8, in some embodimentsaccess point 112 assembles a downlink multi-traffic-identifier (TID)aggregate media access control protocol data unit (AMPDU) having theprimary access category, and then transmits the downlink multi-TID AMPDUto one of electronic devices 110, such as electronic device 110-1. Whenassembling the downlink multi-TID AMPDU, access point 112 may firstinclude data associated with or having the primary access category.However, when there is additional data associated with another accesscategory, which is different from the primary access category, that hasa backoff counter with a predefined value (such as zero), access point112 may preferentially include this additional data in the downlinkmulti-TID AMPDU. Alternatively or additionally, when all the dataassociated with the primary access category has been included in thedownlink multi-TID AMPDU (or has been transmitted) and there is leftoverduration in the downlink multi-TID AMPDU, access point 112 may includeadditional data associated with at least a different access categorythan the primary access category. In some embodiments, after all thedata associated with the primary access category has been included inthe downlink multi-TID AMPDU (or has been transmitted) and there isleftover duration in the downlink multi-TID AMPDU, access point 112 maypad the downlink multi-TID AMPDU (i.e., no additional data associatedwith a different access category is included or transmitted).

In these ways, the communication technique may allow electronic devices110 and access point 112 to communicate data according to associatedaccess categories and, thus, associated QoS requirements. In particular,medium access by different access categories can be treated differently,as specified by access point 112 in the uplink trigger frame.Furthermore, access point 112 may transmit a downlink OFDMA frame and/ora downlink multi-TID AMPDU that preferentially includes data associatedwith a primary access category. Consequently, the communicationtechnique may facilitate improved communication performance for traffichaving higher-priority access categories (and, more generally, betterQoS requirements). These capabilities may improve the user experiencewhen using electronic devices 110 and/or access point 112.

In the described embodiments, processing a packet or frame in one ofelectronic devices 110 and access point 112 includes: receiving wirelesssignals 116 encoding a packet or a frame; decoding/extracting the packetor frame from received wireless signals 116 to acquire the packet orframe; and processing the packet or frame to determine informationcontained in the packet or frame (such as data included in a payload ofthe packet or frame).

In general, communication via the WLAN, when using the communicationtechnique, may be characterized by a variety ofcommunication-performance metrics. For example, thecommunication-performance metric may include: a received signal strength(RSS), a data rate, a data rate for successful communication (which mayalso be referred to as a ‘throughput’), a latency, an error rate (suchas a retry or resend rate), a mean-square error of equalized signalsrelative to an equalization target, inter-symbol interference, multipathinterference, a signal-to-noise ratio (SNR), a width of an eye pattern,a ratio of a number of bytes successfully communicated during a timeinterval (such as 1-10 s) to an estimated maximum number of bytes thatcan be communicated in the time interval (the latter of which issometimes referred to as a ‘capacity’ of a communication channel orlink), and/or a ratio of an actual data rate to an estimated data rate(which is sometimes referred to as ‘utilization’).

Although we describe the network environment shown in FIG. 1 as anexample, in alternative embodiments, different numbers and/or types ofelectronic devices may be present. For example, some embodiments mayinclude more or fewer electronic devices. As another example, in otherembodiments, different electronic devices can be transmitting and/orreceiving packets or frames.

Moreover, while the communication technique was illustrated using accesspoint 112 in the previous discussion, in other embodiments thecommunication technique may be used with other electronic devices, suchas a device in a peer-to-peer network.

FIG. 2 presents a flow diagram illustrating an example method 200 forcommunicating one or more frames in accordance with some embodiments.This method may be performed by an electronic device, such as aninterface circuit in electronic device 110-1 in FIG. 1. Duringoperation, the electronic device may receive, from a second electronicdevice (such as an access point), an uplink trigger frame (operation210) that specifies an access category.

In response to the uplink trigger frame, the electronic device mayoptionally assemble one or more frames (operation 212) thatpreferentially include data associated with the specified accesscategory. Alternatively, the one or more frames may be pre-assembled.

Then, the electronic device transmits the one or more frames (operation214) to the second electronic device.

In some embodiments, the electronic device optionally performs one ormore additional operations (e.g., operation 216). For example, when allthe data associated with the specified access category has beentransmitted or when there is no data associated with the specifiedaccess category, and when there is leftover time in an allocationassociated with the uplink trigger frame, the electronic device maytransmit the one or more frames to the second electronic device withadditional data associated with another access category that isdifferent from the specified access category.

FIG. 3 presents a flow diagram illustrating an example method 300 forproviding an uplink trigger frame in accordance with some embodiments.This method may be performed by an electronic device, e.g., a secondelectronic device, such as an interface circuit in access point 112 inFIG. 1. During operation, the second electronic device provides, to anelectronic device, an uplink trigger frame (operation 310) thatspecifies an access category. Moreover, the access point may provide thetrigger frame using or in conjunction with a contention-window size andan inter-frame spacing associated with the specified access category, sothat there is a difference in how fast different access categoriesaccess a shared medium.

In response to the uplink trigger frame, the second electronic devicereceives one or more frames (operation 312) from the electronic devicewith data associated with the specified access category.

In some embodiments, the second electronic device optionally performsone or more additional operations (operation 314). For example, when allthe data associated with the specified access category has been receivedor when there is no data associated with the specified access category,and when there is leftover time in an allocation associated with theuplink trigger frame, the second electronic device may receive the oneor more frames from the electronic device with additional dataassociated with another access category that is different from thespecified access category.

Furthermore, the second electronic device may assemble a downlink OFDMAframe having a primary access category, where the second electronicdevice may first include data associated with the primary accesscategory in the downlink OFDMA frame. Then, the second electronic devicemay transmit the downlink OFDMA frame to the electronic device. Notethat when all the data associated with the primary access category hasbeen included in the downlink OFDMA frame or when there is no dataassociated with the primary access category, the second electronicdevice may include additional data in the downlink OFDMA frameassociated with another access category that is different from theprimary access category.

Additionally, the second electronic device may assemble a downlinkmulti-TID AMPDU having a primary access category, where the secondelectronic device may first include data associated with the primaryaccess category in the downlink multi-TID AMPDU unless there is dataassociated with another access category, which is different from theprimary access category, that has a backoff counter with a predefinedvalue. Alternatively, the second electronic device may first includedata associated with the primary access category in the downlinkmulti-TID AMPDU and then, when there is leftover duration in thedownlink multi-TID AMPDU, may include additional data associated withanother access category, which is different from the primary accesscategory. Next, the second electronic device may transmit the downlinkmulti-TID AMPDU to the electronic device.

In some embodiments of method 200 (FIG. 2) and/or of method 300 (FIG.3), there may be additional or fewer operations. Moreover, the order ofthe operations may be changed, and/or two or more operations may becombined into a single operation.

In some embodiments, at least some of the operations in method 200 (FIG.2) and/or in method 300 (FIG. 3) are performed by interface circuits inthe electronic device or the second electronic device. For example, atleast some of the operations may be performed by firmware executed by aninterface circuit, such as by firmware associated with a MAC layer, aswell as one or more circuits in a physical layer in the interfacecircuit.

FIG. 4 illustrates a flow diagram of an example of communication betweenelectronic device 110-1 and access point 112, in accordance with someembodiments. In particular, interface circuit 410 in access point 112may communicate with interface circuit 414 in electronic device 110-1using Wi-Fi. During this communication, interface circuit 410 mayprovide an uplink trigger frame 412 that specifies an access category416. Note that access point 112 may transmit uplink trigger frame 412using or in conjunction with a contention-window size and an inter-framespacing associated with the specified access category, so that a backofftime of uplink trigger frame 412 is associated with the specified accesscategory 416.

In response to uplink trigger frame 412, interface circuit 414 mayoptionally assemble 418 one or more frames 420 that preferentiallyinclude data associated with the specified access category 416 (i.e.,data associated with the specified access category 416 receivespreferential treatment over data associated with unspecified accesscategories).

Then, interface circuit 414 may transmit the one or more frames 420 tothe access point 112.

Moreover, when all the data associated with the specified accesscategory has been transmitted or when there is no data associated withthe specified access category 416, and when there is leftover time in anallocation associated with the uplink trigger frame, interface circuit414 may transmit the one or more frames 420 (or one or more additionalframes) to access point 112 with additional data associated with anotheraccess category that is different from the specified access category416.

Furthermore, interface circuit 410 may assemble 422 a downlink OFDMAframe 424 having a primary access category, where interface circuit 410may first include data associated with the primary access category indownlink OFDMA frame 424. However, when all the data associated with theprimary access category has been included in downlink OFDMA frame 424 orwhen there is no data associated with the primary access category,interface circuit 410 may include additional data in downlink OFDMAframe 424 associated with another access category that is different fromthe primary access category. Then, interface circuit 410 may transmitdownlink OFDMA frame 424 to electronic device 110-1.

Alternatively or additionally, interface circuit 410 may assemble 422 adownlink multi-TID AMPDU having a primary access category in thedownlink OFDMA frame 424, where interface circuit 410 may first includedata associated with the primary access category in the downlinkmulti-TID AMPDU unless there is data associated with another accesscategory, which is different from the primary access category, that hasa backoff counter with a predefined value. Alternatively, interfacecircuit 410 may first include data associated with the primary accesscategory in the downlink multi-TID AMPDU and then, when there isleftover duration in the downlink multi-TID AMPDU (or the allocatedresources), may include additional data associated with another accesscategory, which is different from the primary access category.

Representative Embodiments

We now describe embodiments of the communication technique. In thecommunication technique, an uplink multi-user triggered access categorymay be defined for the trigger frame. In particular, as illustrated inFIG. 5, which presents a timing diagram illustrating an example ofcommunication between electronic devices (such as the electronic devicesof FIG. 1), trigger frames 510 may signal or indicate the accesscategory intended for the uplink transmissions, and electronic devicesor stations in a WLAN may respond by transmitting frames 512 that firstinclude data associated with the access category specified in triggerframes 510. In this way, the medium access for different accesscategories can be treated differently, and may be controlled by triggerframes 510.

During the communication technique, when a station receives anallocation in a trigger frame for a specific access category indicatedin the trigger frame, the station may first respond with the trafficfrom that access category. In particular, the data associated with thespecified access category may be included in the immediately followinguplink physical layer convergence protocol (PLCP) protocol data unit(PPDU). When traffic for that particular access category does not exist,or has been transmitted but there is still leftover time in theallocation, the station may be allowed to send traffic from one or moreother access categories (which, as noted previously, is sometimesreferred to as ‘non-triggered access category’).

Moreover, during the communication technique, when an access point sendsa trigger frame, the contention window preceding the trigger frame andthe inter-frame spacing preceding and/or following the trigger frame maybe based on the corresponding access category of the data specified inthe trigger frame. Thus, as shown in FIG. 5, backoff times 514 ofdifferent trigger frames may be different. In this way, thecommunication technique facilitates QoS differentiation in terms of howfast different access-category traffic can get to access the sharedmedium.

FIG. 6 is a block diagram illustrating an example of a trigger frame 600that includes information specifying an access category. In particular,an uplink multi-user triggered access-category (UL MU triggered AC)field 612 may be include into common-information field 610 to indicatewhich access category this trigger frame is meant for.

In summary, to facilitate QoS provisioning in IEEE 802.11ax uplinkmulti-user transmissions, in the communication technique informationspecifying an access category may be included in a trigger frame toindicate the access-category traffic that is to be transmitted in theimmediately following uplink multi-user PPDU. This change to thetrigger-frame format may have a significant impact because it may allowthe QoS aspects that have been defined in previous Wi-Fi networks to bemaintained in IEEE 802.11ax networks. In addition, in the communicationtechnique an access point may send a trigger frame according to QoSrequirements.

As noted previously, a similar challenge can occur during downlinkcommunication. To address this challenge, a primary access category maybe defined in IEEE 802.11ax downlink OFDMA. In particular, the primaryaccess category may be used when an access point uses downlink OFDMA.The access point may acquire the channel according to a particularaccess category and then may first send data to stations from thisprimary access category. If there is no primary access-category trafficfor a particular station, the access point may transmit data from one ormore other access categories to this station.

Inclusion of the primary access category in downlink OFDMA in frequencydomain is illustrated in FIG. 7, which presents a timing diagramillustrating an example of communication between electronic devices,such as the electronic devices of FIG. 1. Note that data 710communicated to different stations (STAs) using in downlink OFDMA mayoccur using different frequencies or channels.

In some embodiments, there may be four backoff counters for thedifferent access categories. When the value of a backoff counter reacheszero, then the access point may acquire the channel or shared mediumaccording to the corresponding access category (which is the primaryaccess category).

IEEE 802.11ax also has defined a multi-TID AMPDU in which traffic frommultiple access categories is aggregated in the time domain. Inparticular, when an access point and a station enable multi-TID AMPDU,there may also be a QoS problem in terms of which access-categorytraffic is allowed to be aggregated in the multi-TID AMPDU. In thecommunication technique, the access point may aggregate traffic foranother access category when the backoff counter of that access categoryhas reached zero. Alternatively or additionally, the access point mayaggregate traffic for another access category as long as there isleft-over duration in this downlink PPDU regardless of the value of thebackoff counter (i.e., when there is leftover allocation, it may beregardless of the access-category backoff counter values). FIG. 8presents a drawing illustrating an example of communicating data 810 todifferent stations using a multi-TID AMPDU 800.

In summary, the communication technique may facilitate QoS Provisioningfor IEEE 802.11ax downlink multi-user OFDMA transmissions. Inparticular, when an access point acquires the channel for a downlinkOFDMA transmission according to a particular access category, thisaccess category may become the primary access category. The accesscategory may send data from the primary access category first to aparticular station. If there is no data from this access category forthis station, then the access point may be allowed to send otheraccess-category traffic. Alternatively, if there is data from thisaccess category for this station, and when multi-TID is supported by theaccess point and the station, then if the access point has exhaustedtransmission of the primary access-category traffic, the access pointcan either pad the rest of the transmission or aggregate traffic fromone or more other access categories into the transmission.

Thus, in the communication technique an access point may control thetype of data that is preferentially transmitted in IEEE 802.11ax. Inparticular, the access point may provide an uplink multi-user triggerframe that includes information or an indication specifying an accesscategory. Moreover, the access point may transmit a downlink OFDMA frameand/or a multi-TID AMPDU that preferentially includes data associatedwith a primary access category.

We now describe embodiments of an electronic device. FIG. 9 presents ablock diagram of an electronic device 900 (which may be an access pointor another electronic device, such as a station) in accordance with someembodiments. This electronic device includes processing subsystem 910,memory subsystem 912, and networking subsystem 914. Processing subsystem910 includes one or more devices configured to perform computationaloperations. For example, processing subsystem 910 can include one ormore microprocessors, application-specific integrated circuits (ASICs),microcontrollers, programmable-logic devices, and/or one or more digitalsignal processors (DSPs).

Memory subsystem 912 includes one or more devices for storing dataand/or instructions for processing subsystem 910 and networkingsubsystem 914. For example, memory subsystem 912 can include dynamicrandom access memory (DRAM), static random access memory (SRAM), aread-only memory (ROM), flash memory, and/or other types of memory. Insome embodiments, instructions for processing subsystem 910 in memorysubsystem 912 include: one or more program modules or sets ofinstructions (such as program module 922 or operating system 924), whichmay be executed by processing subsystem 910. For example, a ROM canstore programs, utilities or processes to be executed in a non-volatilemanner, and DRAM can provide volatile data storage, and may storeinstructions related to the operation of electronic device 900. Notethat the one or more computer programs may constitute a computer-programmechanism, a computer-readable storage medium or software. Moreover,instructions in the various modules in memory subsystem 912 may beimplemented in: a high-level procedural language, an object-orientedprogramming language, and/or in an assembly or machine language.Furthermore, the programming language may be compiled or interpreted,e.g., configurable or configured (which may be used interchangeably inthis discussion), to be executed by processing subsystem 910. In someembodiments, the one or more computer programs are distributed over anetwork-coupled computer system so that the one or more computerprograms are stored and executed in a distributed manner.

In addition, memory subsystem 912 can include mechanisms for controllingaccess to the memory. In some embodiments, memory subsystem 912 includesa memory hierarchy that comprises one or more caches coupled to a memoryin electronic device 900. In some of these embodiments, one or more ofthe caches is located in processing subsystem 910.

In some embodiments, memory subsystem 912 is coupled to one or morehigh-capacity mass-storage devices (not shown). For example, memorysubsystem 912 can be coupled to a magnetic or optical drive, asolid-state drive, or another type of mass-storage device. In theseembodiments, memory subsystem 912 can be used by electronic device 900as fast-access storage for often-used data, while the mass-storagedevice is used to store less frequently used data.

Networking subsystem 914 includes one or more devices configured tocouple to and communicate on a wired and/or wireless network (i.e., toperform network operations), including: control logic 916, an interfacecircuit 918 and a set of antennas 920 (or antenna elements) in anadaptive array that can be selectively turned on and/or off by controllogic 916 to create a variety of optional antenna patterns or ‘beampatterns.’ (While FIG. 9 includes set of antennas 920, in someembodiments electronic device 900 includes one or more nodes, such asnodes 908, e.g., a pad or an electrical connector, which can be coupledto set of antennas 920. Thus, electronic device 900 may or may notinclude set of antennas 920.) For example, networking subsystem 914 caninclude a Bluetooth™ networking system, a cellular networking system(e.g., a 3G/4G/5G network such as UMTS, LTE, etc.), a universal serialbus (USB) networking system, a networking system based on the standardsdescribed in IEEE 802.11 (e.g., a WiFi® networking system), an Ethernetnetworking system, and/or another networking system.

Networking subsystem 914 includes processors, controllers,radios/antennas, sockets/plugs, and/or other devices used for couplingto, communicating on, and handling data and events for each supportednetworking system. Note that mechanisms used for coupling to,communicating on, and handling data and events on the network for eachnetwork system are sometimes collectively referred to as a ‘networkinterface’ for the network system. Moreover, in some embodiments a‘network’ or a ‘connection’ between the electronic devices does not yetexist. Therefore, electronic device 900 may use the mechanisms innetworking subsystem 914 for performing simple wireless communicationbetween the electronic devices, e.g., transmitting advertising or beaconframes and/or scanning for advertising frames transmitted by otherelectronic devices.

Within electronic device 900, processing subsystem 910, memory subsystem912, and networking subsystem 914 are coupled together using bus 928that facilitates data transfer between these components. Bus 928 mayinclude an electrical, optical, and/or electro-optical connection thatthe subsystems can use to communicate commands and data among oneanother. Although only one bus 928 is shown for clarity, differentembodiments can include a different number or configuration ofelectrical, optical, and/or electro-optical connections among thesubsystems.

In some embodiments, electronic device 900 includes a display subsystem926 for displaying information on a display, which may include a displaydriver and the display, such as a liquid-crystal display, a multi-touchtouchscreen, etc. Display subsystem 926 may be controlled by processingsubsystem 910 to display information to a user (e.g., informationrelating to incoming, outgoing, or an active communication session).

Electronic device 900 can also include a user-input subsystem 930 thatallows a user of the electronic device 900 to interact with electronicdevice 900. For example, user-input subsystem 930 can take a variety offorms, such as: a button, keypad, dial, touch screen, audio inputinterface, visual/image capture input interface, input in the form ofsensor data, etc.

Electronic device 900 can be (or can be included in) any electronicdevice with at least one network interface. For example, electronicdevice 900 may include: a cellular telephone or a smartphone, a wirelessdevice, a mobile device, a tablet computer, a laptop computer, anotebook computer, a personal or desktop computer, a netbook computer, amedia player device, an electronic book device, a MiFi® device, asmartwatch, a wearable computing device, a portable computing device, aconsumer-electronic device, an access point, a router, a switch,communication equipment, test equipment, as well as any other type ofelectronic computing device having wireless communication capabilitythat can include communication via one or more wireless communicationprotocols.

Although specific components are used to describe electronic device 900,in alternative embodiments, different components and/or subsystems maybe present in electronic device 900. For example, electronic device 900may include one or more additional processing subsystems, memorysubsystems, networking subsystems, and/or display subsystems.Additionally, one or more of the subsystems may not be present inelectronic device 900. Moreover, in some embodiments, electronic device900 may include one or more additional subsystems that are not shown inFIG. 9. Also, although separate subsystems are shown in FIG. 9, in someembodiments some or all of a given subsystem or component can beintegrated into one or more of the other subsystems or component(s) inelectronic device 900. For example, in some embodiments program module922 is included in operating system 924 and/or control logic 916 isincluded in interface circuit 918.

Moreover, the circuits and components in electronic device 900 may beimplemented using any combination of analog and/or digital circuitry,including: bipolar, PMOS and/or NMOS gates or transistors. Furthermore,signals in these embodiments may include digital signals that haveapproximately discrete values and/or analog signals that have continuousvalues. Additionally, components and circuits may be single-ended ordifferential, and power supplies may be unipolar or bipolar.

An integrated circuit (which is sometimes referred to as a‘communication circuit’) may implement some or all of the functionalityof networking subsystem 914. This integrated circuit may includehardware and/or software mechanisms that are used for transmittingwireless signals from electronic device 900 and receiving signals atelectronic device 900 from other electronic devices. Aside from themechanisms herein described, radios are generally known in the art andhence are not described in detail. In general, networking subsystem 914and/or the integrated circuit can include any number of radios. Notethat the radios in multiple-radio embodiments function in a similar wayto the described single-radio embodiments.

In some embodiments, networking subsystem 914 and/or the integratedcircuit include a configuration mechanism (such as one or more hardwareand/or software mechanisms) that configures the radio(s) to transmitand/or receive on a given communication channel (e.g., a given carrierfrequency). For example, in some embodiments, the configurationmechanism can be used to switch the radio from monitoring and/ortransmitting on a given communication channel to monitoring and/ortransmitting on a different communication channel. (Note that‘monitoring’ as used herein comprises receiving signals from otherelectronic devices and possibly performing one or more processingoperations on the received signals)

In some embodiments, an output of a process for designing the integratedcircuit, or a portion of the integrated circuit, which includes one ormore of the circuits described herein may be a computer-readable mediumsuch as, for example, a magnetic tape or an optical or magnetic disk.The computer-readable medium may be encoded with data structures orother information describing circuitry that may be physicallyinstantiated as the integrated circuit or the portion of the integratedcircuit. Although various formats may be used for such encoding, thesedata structures are commonly written in: Caltech Intermediate Format(CIF), Calma GDS II Stream Format (GDSII) or Electronic DesignInterchange Format (EDIF). Those of skill in the art of integratedcircuit design can develop such data structures from schematic diagramsof the type detailed above and the corresponding descriptions and encodethe data structures on the computer-readable medium. Those of skill inthe art of integrated circuit fabrication can use such encoded data tofabricate integrated circuits that include one or more of the circuitsdescribed herein.

While the preceding discussion used a Wi-Fi communication protocol as anillustrative example, in other embodiments a wide variety ofcommunication protocols and, more generally, wireless communicationtechniques may be used. Thus, the communication technique may be used ina variety of network interfaces. Furthermore, while some of theoperations in the preceding embodiments were implemented in hardware orsoftware, in general the operations in the preceding embodiments can beimplemented in a wide variety of configurations and architectures.Therefore, some or all of the operations in the preceding embodimentsmay be performed in hardware, in software or both. For example, at leastsome of the operations in the communication technique may be implementedusing program module 922, operating system 924 (such as a driver forinterface circuit 918) or in firmware in interface circuit 918.Alternatively or additionally, at least some of the operations in thecommunication technique may be implemented in a physical layer, such ashardware in interface circuit 918. In an exemplary embodiment, thecommunication technique is implemented, at least in part, in a MAC layerand/or in a physical layer in interface circuit 918.

Representative Embodiments

In some embodiments, an electronic device includes an interface circuitconfigured to: communicate with an access point of a wireless local areanetwork (WLAN); receive, from the access point of the WLAN, an uplinktrigger frame that specifies an access category; and, in response to theuplink trigger frame, transmit to the access point of the WLAN one ormore frames that include data associated with the specified accesscategory.

In some embodiments, the electronic device includes a wireless station.In some embodiments, the uplink trigger frame includes a multi-usertrigger frame. In some embodiments, the interface circuit of theelectronic device is further configured to: in response to the uplinktrigger frame, transmit to the access point of the WLAN additional dataassociated with another access category that differs from the specifiedaccess category, when: (i) all the data associated with the specifiedaccess category has been transmitted or there is no data associated withthe specified access category, and (ii) additional transmission timeremains in an allocation associated with the uplink trigger frame inwhich to transmit the additional data. In some embodiments, the uplinktrigger frame is preceded by a contention-window size and is followed byan inter-frame spacing associated with the specified access category. Insome embodiments, the electronic device includes an antennacommunicatively coupled to the interface circuit via one or moreelectrical connectors. In some embodiments, the interface circuit of theelectronic device is further configured to receive, from the accesspoint of the WLAN, a downlink orthogonal frequency-division multipleaccess (OFDMA) frame that includes data associated with at least twodifferent access categories. In some embodiments, the interface circuitof the electronic device is further configured to receive, from theaccess point of the WLAN, a downlink multi-traffic-identifier (TID)aggregate media access control protocol data unit (AMPDU) that includesdata associated with at least two different access categories. In someembodiments, the uplink trigger frame includes a multi-user triggerframe.

In some embodiments, an electronic device includes an interface circuitconfigured to: communicate with a wireless station; provide, to thewireless station, an uplink trigger frame that specifies an accesscategory; and, in response to the uplink trigger frame, receive from thewireless station, one or more frames that include data associated withthe specified access category.

In some embodiments, the electronic device includes an access point. Insome embodiments, the uplink trigger frame includes a multi-user triggerframe. In some embodiments, the interface circuit of the electronicdevice is further configured to receive, from the wireless station,additional data associated with another access category that isdifferent from the specified access category, when: (i) all the dataassociated with the specified access category has been received or thereis no data associated with the specified access category, and (ii)additional reception time remains in an allocation associated with theuplink trigger frame in which to receive the additional data. In someembodiments, the uplink trigger frame is transmitted using acontention-window size and an inter-frame spacing associated with thespecified access category, and different access categories are grantedaccess to a shared medium for communication at different rates. In someembodiments, the electronic device includes an antenna communicativelycoupled to the interface circuit via one or more electrical connectors.In some embodiments, the interface circuit of the electronic device isfurther configured to: (i) assemble a downlink orthogonalfrequency-division multiple access (OFDMA) frame having a primary accesscategory, the electronic device first including data associated with theprimary access category in the downlink OFDMA frame; and (ii) transmitthe downlink OFDMA frame to the wireless station. In some embodiments,the interface circuit of the electronic device is further configured to:include additional data in the downlink OFDMA frame associated withanother access category that differs from the primary access category,when all the data associated with the primary access category isincluded in the downlink OFDMA frame or when there is no data associatedwith the primary access category. In some embodiments, the interfacecircuit of the electronic device is further configured to: (i) assemblea downlink multi-traffic-identifier (TID) aggregate media access controlprotocol data unit (AMPDU) having a primary access category, theelectronic device first including data associated with the primaryaccess category in the downlink multi-TID AMPDU unless there is dataassociated with another access category, which differs from the primaryaccess category, that has a backoff counter with a predefined value; and(ii) transmit the downlink multi-TID AMPDU to the wireless station. Insome embodiments, the interface circuit of the electronic device isfurther configured to: (i) assemble a downlink multi-traffic-identifier(TID) aggregate media access control protocol data unit (AMPDU) having aprimary access category, the electronic device first including dataassociated with the primary access category in the downlink multi-TIDAMPDU and, when additional space remains in the downlink multi-TIDAMPDU, include additional data associated with another access category,which differs from the primary access category; and (ii) transmit thedownlink multi-TID AMPDU to the wireless station.

In some embodiments, a method for receiving one or more frames via aninterface circuit of an access point includes: (i) providing, to awireless station, an uplink trigger frame that specifies an accesscategory; and (ii) in response to the uplink trigger frame, receivingfrom the wireless station the one or more frames that include dataassociated with the specified access category. In some embodiments, theuplink trigger frame is preceded by a contention-window size and isfollowed by an inter-frame spacing associated with the specified accesscategory.

In the preceding description, we refer to ‘some embodiments.’ Note that‘some embodiments’ describes a subset of all of the possibleembodiments, but does not always specify the same subset of embodiments.

The foregoing description is intended to enable any person skilled inthe art to make and use the disclosure, and is provided in the contextof a particular application and its requirements. Moreover, theforegoing descriptions of embodiments of the present disclosure havebeen presented for purposes of illustration and description only. Theyare not intended to be exhaustive or to limit the present disclosure tothe forms disclosed. Accordingly, many modifications and variations willbe apparent to practitioners skilled in the art, and the generalprinciples defined herein may be applied to other embodiments andapplications without departing from the spirit and scope of the presentdisclosure. Additionally, the discussion of the preceding embodiments isnot intended to limit the present disclosure. Thus, the presentdisclosure is not intended to be limited to the embodiments shown, butis to be accorded the widest scope consistent with the principles andfeatures disclosed herein.

What is claimed is:
 1. An electronic device, comprising: one or moreelectrical connectors configured to communicatively couple to anantenna; and an interface circuit, communicatively coupled to the one ormore electrical connectors, configured to communicate with an accesspoint of a wireless local area network (WLAN), and configured to:receive, from the access point of the WLAN, an uplink trigger frame thatspecifies an access category; and in response to the uplink triggerframe, transmit to the access point of the WLAN one or more frames thatinclude data associated with the specified access category.
 2. Theelectronic device of claim 1, wherein the uplink trigger frame includesa multi-user trigger frame.
 3. The electronic device of claim 1, whereinthe interface circuit is further configured to: in response to theuplink trigger frame, transmit to the access point of the WLANadditional data associated with another access category that differsfrom the specified access category, when: (i) all the data associatedwith the specified access category has been transmitted or there is nodata associated with the specified access category, and (ii) additionaltransmission time remains in an allocation associated with the uplinktrigger frame in which to transmit the additional data.
 4. Theelectronic device of claim 1, wherein the uplink trigger frame ispreceded by a contention-window size and is followed by an inter-framespacing associated with the specified access category.
 5. The electronicdevice of claim 1, wherein the electronic device further comprises theantenna communicatively coupled to the one or more electricalconnectors.
 6. The electronic device of claim 1, wherein the interfacecircuit is further configured to receive, from the access point of theWLAN, a downlink orthogonal frequency-division multiple access (OFDMA)frame that includes data associated with at least two different accesscategories.
 7. The electronic device of claim 1, wherein the interfacecircuit is further configured to receive, from the access point of theWLAN, a downlink multi-traffic-identifier (TID) aggregate media accesscontrol protocol data unit (AMPDU) that includes data associated with atleast two different access categories.
 8. The electronic device of claim1, wherein the uplink trigger frame includes a multi-user trigger frame.9. An electronic device, comprising: one or more electrical connectorsconfigured to communicatively couple to an antenna; and an interfacecircuit, communicatively coupled to the one or more electricalconnectors, configured to communicate with a wireless station, andconfigured to: provide, to the wireless station, an uplink trigger framethat specifies an access category; and in response to the uplink triggerframe, receive from the wireless station, one or more frames thatinclude data associated with the specified access category.
 10. Theelectronic device of claim 9, wherein the electronic device comprises anaccess point.
 11. The electronic device of claim 9, wherein the uplinktrigger frame includes a multi-user trigger frame.
 12. The electronicdevice of claim 9, wherein, the interface circuit is further configuredto: receive, from the wireless station, additional data associated withanother access category that is different from the specified accesscategory, when: (i) all the data associated with the specified accesscategory has been received or there is no data associated with thespecified access category, and (ii) additional reception time remains inan allocation associated with the uplink trigger frame in which toreceive the additional data.
 13. The electronic device of claim 9,wherein: the uplink trigger frame is transmitted using acontention-window size and an inter-frame spacing associated with thespecified access category; and different access categories are grantedaccess to a shared medium for communication at different rates.
 14. Theelectronic device of claim 9, wherein the electronic device furthercomprises the antenna communicatively coupled to the one or moreelectrical connectors.
 15. The electronic device of claim 9, wherein theinterface circuit is further configured to: assemble a downlinkorthogonal frequency-division multiple access (OFDMA) frame having aprimary access category, the electronic device first including dataassociated with the primary access category in the downlink OFDMA frame;and transmit the downlink OFDMA frame to the wireless station.
 16. Theelectronic device of claim 15, wherein the interface circuit is furtherconfigured to: when all the data associated with the primary accesscategory is included in the downlink OFDMA frame or when there is nodata associated with the primary access category, include additionaldata in the downlink OFDMA frame associated with another access categorythat differs from the primary access category.
 17. The electronic deviceof claim 9, wherein the interface circuit is further configured to:assemble a downlink multi-traffic-identifier (TID) aggregate mediaaccess control protocol data unit (AMPDU) having a primary accesscategory, the electronic device first including data associated with theprimary access category in the downlink multi-TID AMPDU unless there isdata associated with another access category, which differs from theprimary access category, that has a backoff counter with a predefinedvalue; and transmit the downlink multi-TID AMPDU to the wirelessstation.
 18. The electronic device of claim 9, wherein the interfacecircuit is further configured to: assemble a downlinkmulti-traffic-identifier (TID) aggregate media access control protocoldata unit (AMPDU) having a primary access category, the electronicdevice first including data associated with the primary access categoryin the downlink multi-TID AMPDU and, when additional space remains inthe downlink multi-TID AMPDU, include additional data associated withanother access category, which differs from the primary access category;and transmit the downlink multi-TID AMPDU to the wireless station.
 19. Amethod for receiving one or more frames, the method comprising: using aninterface circuit in an access point to: provide, to a wireless station,an uplink trigger frame that specifies an access category; and inresponse to the uplink trigger frame, receive from the wireless stationthe one or more frames that include data associated with the specifiedaccess category.
 20. The method of claim 19, wherein the uplink triggerframe is preceded by a contention-window size and is followed by aninter-frame spacing associated with the specified access category.